Reversible synchronous rerecording system



July 12, 1966 A, P. GREEN ETAL REVERSIBLE SYNCHRONOUS RERECORDING SYSTEM Original Filed Oct. 12, 1962 INVENTORI BY @Km Armen/5y United States Patent O 3,260,909 REVERSIBLE SYNCSI-{OIOUS RERECORDING T This invention relates to .a motion picture sound track rerecording system, and p-articularly to a load motor control to permit forward and reverse advancement of a plurality of films in synchronisrn at all times. This application is a continuation of application Serial No. 230,- 220, tiled October 12, 1962, now abandoned, entitled Reversible Synchronous Rerecording System.

The use of selsyn or self-synchronous interconnected motor systems is well known, -as evidenced by Kellogg U.S. Patent No. 2,295,664, Miller U.S. Patent No. 2,354,- 329, Bloomberg et al. U.S. Patent No, 2,445,820, and Hit-tlc et al. U.S. Patent No. 2,833,972.

The general principle of operation of such systems is the use of a three-phase synchronous drive motor mechanically driving a distributor or rotating transformer which has its rotor connected to the rotors of the load motors `and its stator connected to the stators of the load motors.

In the production of motion pictures, the picture is rusually recorded on a picture tilm, Iand the dialogue and music are recorded on a separate sound iilrn which may 'be -a photographic or magnetic recording or a combination of both. Subsequently, other background sounds from photographic or magnetic films are introduced into the dialogue record, such sounds being of different characters, such as hoofbeats, thunder, music, etc., which are used to enhance the depicting of the picture story. Each of the iilms is reproduced in separate sound reproducers driven in synohronism by individual load motors.

T o obtain the proper balance between the ampli-tudes and positions of the sound sequences of the various sound tracks with respect to one another, the sequences are rehearsed several times. During rehearsal, thousand-toot Ireels and loops are generally used, seach reel containing a number of sequences.

During the tirst rehearsal period, certain of the sound records are properly mixed, while others may not be and can be improved. Thus, it is necessary to repeat the undesired combination of sound sequences in order to provide the desired over-all combination. In the Ipast, it has been necessary to run all of the reels out, then rewind the reels and again set their sync mark fora rerun of the entire reels and loops. It is obvious that not only is this time-consuming but provides opportunities for film damage and for errors in previously properly mixed sequences.

The .present invention contemplates la system whereby the many motors driving the several sound reproducers, picture projector, etc., may be reversed at any time during reproduction of the various records without losing synchronism. This permits the sequences within the reels to be repeated as often as necessary regardless of their positions within the reels and the length of t-he reels. After the `repeated sequences are satisfactory, rerecording of t-he remaining sequences inthe reels or loops is continued. It is, therefore, unnecessary to Arun the films to their ends,

' may not be used for increasing A is a reversing switch 3,260,909 Patented July l2, 1966 ice -rewind and rethread them, which will repeat the satisfactorily mixed sequences, and which is not desired.

To obtain reversal of the drive motor, distributor, and the load motors which have various loads thereon, it is necessary to properly control the energization and deenergization of the drive motor, distributor, and load motors in a special m-anner. The present invention permits this operation for the irst time without losing sync of -any load motor with respect to the others regardless of the variation in loads on the load motors.

The principal object of the invention, therefore, is to facilitate the rerecording of multiple sound reco-rds into a single record.

, Another object of the invention is to provide an improved method of and system for rerecording which permits the repetition of any particular sequences within reels without losing sync with other records being combined to a single record.

A further object of the invention is to provide an improved control for a self-synchronous motor drive syste-m which permits a reversal of all load motors in synchronism together with a counting system which indicates the film footage at all times regardless of the direction of advancement of the various films, the sounds on which are being combined.

A better understanding ot this invention may be had from the following detailed description when read in conjunction with the single figure, which is a diagrammatic cir-cuit embodying the invention.

Referring, now, to the drawing, a three-phase synchronous drive moto-r 5 is connected by a shaft 6 to a distributor or rotating transformer 7. A brake 8 may or the deceleration of the motor 5 and distributor 7. On a shaft 10 of 4the drive motor is a cam wheel12 having three cams 13 spaced 120 degrees apart, although other forms of devi-ces may be used.

Power is supplied from three-phase conductors 16 connected to switch A for one phase of the 60-cycle power supply, and switch B for the other two phases of the power supply.

The synchronous drive motor 5 has windings 18 connectable to the three-phase 60-cycle power supply over switch C, while stator windings 19 of the distributor 7 are similarly connectable to 4the power supply. Switch which when thrown to its lower position will apply energy to conductors 21 of the distributor stator and conductors 22, which go to switch C, of the synchronous drive motor with a certain polarity. When switch A is thrown to its upper position, these conductors 21 and 22 will be reversed. It will be noted by the dotted lines 24 that switch B is mechanically connected to switch C, and these switches are thus actuated simultaneously to start the motor 5 and distributor 7 in either direction, depending upon the position of switch A.

The rotor 9 of the distributor 7 is connected over conductors 25 to the rotors of load motors No. l, No. 2, and No. 3, and to the Vrotors of any other load motors, the number of which may at times be .in the neighborhood of from -twenty to thirty. The stator 19 of the distributor is connected over conductors 26 to the stators of load motors No. l, No. 2, and No. 3, and yto the stators of any other load motors, which may at times be in the neighborhood of from twenty to thirty motors. Thus, when switch A reverses the distributor conductors 21 and impulse-producing the synchronous drive motor conductors 22, the phase of Ithe stators of all the load motors will also be reversed.

It is well known that to operate such a system, the speed of the distributor is such that the interlock frequency of the current generated in the distributor rotor 19 is the right frequency to provide the tightest interlock for the particular system.

In this system, the rotor of the distributor rotates at a speed to generate 40 cycles per second. Thus, the interlocking frequency `of the current in the conductors 25 to the rotors of the load motors is 60-40 or 20 cycles per second. This frequency of the interlocking current has been found to be the optimum for such a self-synchronous modification of the usual type of self-synchronous drive motor system for rerecording, it is one which will permit the reversal of any length of tilm and the repetition thereof as many times as necessary and at optimums conditions of interlock at all times.

The above system manner by rst threading the lm in the projector and the lms by their respective load motors. will energize conductors load motors which will This action 21 and 22 and one phase of the align the distributor and load hold or lock-up positions.

and load motors. accelerated in synchronisum until the desired speed is reached and will then remain in synchronism when advanced at uniform speed.

top the system, it is only necessary to open switches To s B and C, which will original positions. If rerecording is completed, the switch A is opened.

Now, to reverse the system, switch A is thrown to its upper contacts, reversing the conductors 21 and 22 and the phase of the stators of the load motors.

rotated in the forward direction.

Referring, now, to the film-counting portion of the system, a switch 30 is actuated by the cams 13 of the disc 12 three times per revolution of the disc.

39 to a forward counting relay 32 and a reverse counting relay 33 to the swinger 34 of a relay 35. The relay 35 is actuated by a switch 36 in series with a power supply 37.

i The normal position of the swinger 34 is as shown in the drawing which connects the forward counting relay 32 with the switch 30. When the switch 36 is actuated, the swinger 34 is moved to its lower contact which connects the switch 30 to the reverse counting relay 33. The counting relay consists of a toothed wheel 40 and a reversing pawl 41. Thus, the impulse actuation of relay 32 will move the pawl one notch while the actuation of relay 33 will reverse the pawl one notch, the pawl 40 being a unit pawl which may indicate feet or frames, other indicia counting wheels of a normal multiple counter system being connected thereto. Thus, when the motor system is reversed by actuating switch A, switch 36 may be simulproduced or the position of the ilm during reversal.

The counter system may be provided with means for actua-ting switches B and C at any predetermined point between the ends of the lm on the reels and particularly at the ends of the tilm reels to prevent runouts at either end.

As mentioned above, such a reversal system for a selfsynchronous motor driven sound rerecording system permits repeating sequences on multiple films at any point between the ends of the reels with reliability with respect to the loss of sync. Thus, much time is saved as well as reducing the handling of the many lms used in re-v phase power source, rotor winding and sald rotor windings of said load motors, means for simultaneously connecting one phase of motor, said one phase of said distributor stator winding, and said one phase of said load motor stator windings, said second-mentioned means being adapted to subsequently and simultaneously connect the other two phases of said power source to the other two phases of said distributor stator winding, the other two phases of said load motor phases of said drive motor, thereby causing said drive motor, said distributor, and said load motors to run in are provided for counting and drive motor in both directions of rotation.

3. A system in accordance with claim 1 in which the frequency of the current of said power source is 60 cycles per second, the output frequency of the current from said 4. In a system for maintaining the optimum interlocking synchronous frequency between any combination of a plurality of sound reproducing machines, at least one recording machine, and at least one motion picture projector, said machines and projector having load motors, a distributor, and a synchronous drive motor for said distributor, each of said load motors and said distributor having stator and rotor windings, said drive motor, said distributor, and said load motors being adapted to be connected to a three-phase power source, means for connecting said load motors, said three-phase source to drive said motors in a certain direction, the frequency of said threephase source providing the optimum frequency of the interlocking current between said load motors and said distributor, and means for driving said load motors in the reverse direction with the same frequency as the interlocking frequency of the current between said load motors and said distributor, said interlocking current being obtained by reversing one phase of said drive motor, distributor, and said load motors.

5. A system in accordance with claim 4 in which the frequency of current of said three-phase source is 60 cycles per second and the frequency of the interlocking current between said distributor and said load motors is 20 cycles per second in either direction of rotation.

6. A system in accordance with claim 4 number of rotations of said distributor is counted when said distributor is rotated in either direction,

7. In a system for maintaining synchronism between any combination of the plurality of movable sound reproducing or recording machines and motion picture projectors when driven in either direction comprising a synchronous drive motor, a distributor mechanically connected to said drive motor, said distributor having stator and rotor windings and said drive motor having threephase windings, a plurality of load motors, each of which has a stator windings and a rotor winding, means for interconnecting said rotor windings of said load motors and said rotor winding of said distributor to transmit interlocking current of a certain frequency from said distributor to said load motors, means for interconnecting said stator windings of said load motors, said stator winding of said distributor, and the winding of said drive motor, said drive motor windings, said windings of said load motors, and said winding of said distributor being adapted to be connected to a three-phase power source, and switching means for making a said last-mentioned connections, said switching means including a iirst means for first simultaneously connecting one phase of said three-phase power source to one phase of said distributor stator winding, one phase of said load motor stator windings, and a second means for subsequently and simultaaneously connecting the other two phases of said power source to the other two phases of said load motor stator windings, the other two phases of said distributor stator winding and the three phases of said drive motor, said first means being adapted to reverse the connections of said one first -mentioned phase of said power source to said first-mentioned phase of said load motor stator windings, said distributor stator winding and said first-mentioned phase of said drive motor to reverse the direction of rotation of said drive motor, said distribin which the utor and said load motors, said load motors rotating in their original synchronous position at all times in either direction and with an interlocking current of said certain frequency.

8. A system in accordance with claim 7 in which said interlocking current has the same frequency in each direction of rotation of said load motors, said frequency being determined by the difference between the frequency of the current from said power source and the frequency of the current from said distributor, the frequency of said interlocking current being the optimum frequency to maintain synchronism of said load motors in either direction of rotation thereof.

9. A system in accordance with claim '7 in which a rotation counting system is provided, said system including means for connecting said system to said drive motor and switching means for reversing the direction of rotation of said counting system, said means being interconnected with said reversing switching means for said motors.

10. In a system for maintaining synchronism between any combination of a plurality of sound reproducing machines or recording machines and atleast one motion picture projector when driven in either direction, a synchronous drive motor, a distributor having stator and rotor windings, a plurality of load motors to be driven in synchronism with each other, each of said load motors having stator and rotor windings, said drive motor, said distributor, and said load motors being adapted to be connected to a three-phase power source, connections between said rotor winding of said distributor and the rotor windings of said load motors, a first switch for simultaneously connecting one phase of said power source through said first switch to one phase of said distributor stator winding and one phase of each of said stator windings of said load motors, and a second switch for subsequently and simultaneously connecting through said second switch the two other phases of said power source to the three phases of said drive m-otor winding, the other two phases of said distributor stator winding and the other two phases of said load motor stator windings for driving said load motors in synhcronism in one direction, said first-mentioned switch being adapted to simultaneously reverse said first-mentioned phase of said power source as impressed on said one phase of said drive motor, said one phase of said distributor stator winding, and said one phase of each of said load motors stator windings to drive said load motors in synchronism at all times in either the reverse direction or their original direction when said second switch is closed.

11. A system in accordance with claim 10 in which a rotation counting system is provided, said system including a third switch mechanically connected to said rst switch for reversing the operation of said counting system.

12. In a system for maintaining the optimum interlock frequency between any combination of a plurality of sound reproducing or recording machines and at least one motion picture projector when said machines and projector are driven in either forward or reverse direction, said machines and said .projector having load motors, a distributor, and a synchronous drive motor for said distributor, each of said load motors and said distributor having stator and rotor windings, said drive motor, said distributor, and said load motors being adapted to be connected to a three-phase power source, means for starting said load motors in forward direction by first simultaneously connecting one phase of a three-phase power source to one phase of the stator windings of each of said load motors and to one phase of the stator winding of said distributor having the rotor windings thereof connected in parallel to the rotor windings of said load motors, and means for simultaneously connecting the other two phases of said power source to the other two phases of said distributor stator windings and the stator windings of said load motors and means for connecting the three phases of said power source to the three phase windings of said distributor drive motor, and means for reversing the direction of said load motors in synchronism with the same synchronization of said load moto-rs when driven in said forward direction by first simultaneously disconnecting said three phase windings of said drive motor from said three-phase power source and said two phases of said power source from said two phases of said distributor and load moto-r stator windings, second simultaneously connecting said one phase of said distributor and load motor stator windings to said three-phase power source in reverse to said forward driving connections, `and means for simultaneously connecting the other two phases stator windings of said distributor and load motors and for optimum interlock in both directions.

13. A system in accordance with claim 12 in which 8 References Cited bythe Examiner UNITED STATES PATENTS 2,304,355 12/1942 Haynes 2,310,339 2/1943 Arndt 2,782,349 2/ 1957 Sharp 2,844,070 7/ 1958 Dresser MAX L. LEVY, Primary Examiner.

means are provided for continuously measuring the rota- 10 ORIS L' KADER Examiner' tion of said load motors in both directions.

T. LYNCH, Assistant Examiner. 

4. IN A SYSTEM FOR MAINTAINING THE OPTIMUM INTERLOCKING SYNCHRONOUS FREQUENCY BETWEEN ANY COMBINATION OF A PLURALITY OF SOUND REPRODUCING MACHINES, AT LEAST ONE RECORDING MACHINE, AND AT LEAST ONE MOTION PICTURE PROJECTOR, SAID MACHINES AND PROJECTORS HAVING LOAD MOTORS, A DISTRIBUTOR, AND A SYNCHRONOUS DRIVE MOTOR FOR SAID DISTRIBUTER, EACH OF SAID LOAD MOTORS AND SAID DISTRIBUTOR HAVING STATOR AND ROTOR WINDINGS, SAID DRIVE MOTOR, SAID DISTRIBUTOR, AND SAID LOAD MOTORS BEING ADAPTED TO BE CONNECTED TO A THREE-PHASE POWER SOURCE, MEANS FOR CONNECTING SAID LOAD MOTORS, SAID THREE-PHASE SOURCE TO DRIVE SAID MOTORS IN A CERTAIN DIRECTION, THE FREQUENCY OF SAID THREEPHASE SOURCE PROVIDING THE OPTIMUM FREQUENCY OF THE INTERLOCKING CURRENT BETWEEN SAID LOAD MOTORS AND SAID DISTRIBUTOR, AND MEANS FOR DRIVING SAID LOAD MOTORS IN THE REVERSE DIRECTION WITH THE SAME FREQUENCY AS THE INTERLOCKING FREQUENCY OF THE CURRENT BETWEEN SAID LOAD MOTORS AND SAID DISTRIBUTOR, SAID INTERLOCKING CURRENT BEING OBTAINED BY REVERSING ONE PHASE OF SAID DRIVE MOTOR, DISTRIBUTOR, AND SAID LOAD MOTORS. 